python-2.7 - Python 2.7，画中画 : "Failed building wheel for ..."

Question

第一次使用pip，尝试使用the python-docs-samples tutorial library .当我运行“python -m pip install -r requirements.txt”命令时，会拉入很多脚本，但随后会出现一系列“构建轮失败”错误。其中之一显示在附加的代码块中(请原谅手动输入的自动换行换行符)。

问题是什么？有人见过这个吗？我没有更改库的任何部分或使用它的代码，我使用的是 Python 2.7.12，它应该对 PIP 具有良好的内置支持。

  Running setup.py bdist_wheel for PyYAML ... error
  Complete output from command C:\users\owner\python-docs-samples\env\Scripts\python.exe 
-u -c "import setuptools, tokenize;__file__='c:\\users\\owner\\appdata\\local\\temp\\
pip-build-86ysrg\\PyYAML\setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__)
.read().replace('\r\n', '\n'), __file__, 'exec'))" bdist_wheel -d c:\users\owner\appdata
\local\temp\tmpljy6z0pip-wheel- --python-tag cp27:
  running bdist_wheel
  running build
  running build_py
  creating build
  creating build\lib.win32-2.7
  creating build\lib.win32-2.7\yaml
  copying lib\yaml\composer.py -> build\lib.win32-2.7\yaml
  copying lib\yaml\constructor.py -> build\lib.win32-2.7\yaml
  copying lib\yaml\cyaml.py -> build\lib.win32-2.7\yaml
  copying lib\yaml\dumper.py -> build\lib.win32-2.7\yaml
  copying lib\yaml\emitter.py -> build\lib.win32-2.7\yaml
  copying lib\yaml\error.py -> build\lib.win32-2.7\yaml
  copying lib\yaml\events.py -> build\lib.win32-2.7\yaml
  copying lib\yaml\loader.py -> build\lib.win32-2.7\yaml
  copying lib\yaml\nodes.py -> build\lib.win32-2.7\yaml
  copying lib\yaml\parser.py -> build\lib.win32-2.7\yaml
  copying lib\yaml\reader.py -> build\lib.win32-2.7\yaml
  copying lib\yaml\representer.py -> build\lib.win32-2.7\yaml
  copying lib\yaml\resolver.py -> build\lib.win32-2.7\yaml
  copying lib\yaml\scanner.py -> build\lib.win32-2.7\yaml
  copying lib\yaml\serializer.py -> build\lib.win32-2.7\yaml
  copying lib\yaml\tokens.py -> build\lib.win32-2.7\yaml
  copying lib\yaml\__init__.py -> build\lib.win32-2.7\yaml
  running build_ext
  creating build\temp.win32-2.7
  creating build\temp.win32-2.7\Release
  checking if libyaml is compilable
  error: [Error 2] The system cannot find the file specified

  ----------------------------------------
  Failed building wheel for PyYAML
  Running setup.py clean for PyYAML

Answer 1

在安装 pyyaml 之前，我通过升级 pip、setuptools 和 wheel 消除了同样的错误:

# Ensure pip, setuptools, and wheel are up to date before installing python packages.
pip install --upgrade pip \
    setuptools \
    wheel \

# Now install various python packages
pip install \
    pyyaml==5.3.1 \
    . . .